/*
 * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
 * Released under the terms of the GNU GPL v2.0.
 */

#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include <sys/utsname.h>

#include "lkc.h"

struct symbol symbol_yes = {
	.name = "y",
	.curr = { "y", yes },
	.flags = SYMBOL_CONST | SYMBOL_VALID,
}, symbol_mod = {
	.name = "m",
	.curr = { "m", mod },
	.flags = SYMBOL_CONST | SYMBOL_VALID,
}, symbol_no = {
	.name = "n",
	.curr = { "n", no },
	.flags = SYMBOL_CONST | SYMBOL_VALID,
}, symbol_empty = {
	.name = "",
	.curr = { "", no },
	.flags = SYMBOL_VALID,
};

struct symbol* sym_defconfig_list;
struct symbol* modules_sym;
tristate modules_val;

struct expr* sym_env_list;

static void sym_add_default(struct symbol* sym, const char* def)
{
	struct property* prop = prop_alloc(P_DEFAULT, sym);

	prop->expr = expr_alloc_symbol(sym_lookup(def, SYMBOL_CONST));
}

void sym_init(void)
{
	struct symbol* sym;
	struct utsname uts;
	static bool inited = false;

	if(inited)
		return;

	inited = true;

	uname(&uts);

	sym = sym_lookup("UNAME_RELEASE", 0);
	sym->type = S_STRING;
	sym->flags |= SYMBOL_AUTO;
	sym_add_default(sym, uts.release);
}

enum symbol_type sym_get_type(struct symbol* sym)
{
	enum symbol_type type = sym->type;

	if(type == S_TRISTATE) {
		if(sym_is_choice_value(sym) && sym->visible == yes)
			type = S_BOOLEAN;
		else if(modules_val == no)
			type = S_BOOLEAN;
	}

	return type;
}

const char* sym_type_name(enum symbol_type type)
{
	switch(type) {
		case S_BOOLEAN:
			return "boolean";

		case S_TRISTATE:
			return "tristate";

		case S_INT:
			return "integer";

		case S_HEX:
			return "hex";

		case S_STRING:
			return "string";

		case S_UNKNOWN:
			return "unknown";

		case S_OTHER:
			break;
	}

	return "???";
}

struct property* sym_get_choice_prop(struct symbol* sym)
{
	struct property* prop;

	for_all_choices(sym, prop)
	return prop;
	return NULL;
}

struct property* sym_get_env_prop(struct symbol* sym)
{
	struct property* prop;

	for_all_properties(sym, prop, P_ENV)
	return prop;
	return NULL;
}

static struct property* sym_get_default_prop(struct symbol* sym)
{
	struct property* prop;

	for_all_defaults(sym, prop) {
		prop->visible.tri = expr_calc_value(prop->visible.expr);

		if(prop->visible.tri != no)
			return prop;
	}
	return NULL;
}

static struct property* sym_get_range_prop(struct symbol* sym)
{
	struct property* prop;

	for_all_properties(sym, prop, P_RANGE) {
		prop->visible.tri = expr_calc_value(prop->visible.expr);

		if(prop->visible.tri != no)
			return prop;
	}
	return NULL;
}

static long long sym_get_range_val(struct symbol* sym, int base)
{
	sym_calc_value(sym);

	switch(sym->type) {
		case S_INT:
			base = 10;
			break;

		case S_HEX:
			base = 16;
			break;

		default:
			break;
	}

	return strtoll(sym->curr.val, NULL, base);
}

static void sym_validate_range(struct symbol* sym)
{
	struct property* prop;
	int base;
	long long val, val2;
	char str[64];

	switch(sym->type) {
		case S_INT:
			base = 10;
			break;

		case S_HEX:
			base = 16;
			break;

		default:
			return;
	}

	prop = sym_get_range_prop(sym);

	if(!prop)
		return;

	val = strtoll(sym->curr.val, NULL, base);
	val2 = sym_get_range_val(prop->expr->left.sym, base);

	if(val >= val2) {
		val2 = sym_get_range_val(prop->expr->right.sym, base);

		if(val <= val2)
			return;
	}

	if(sym->type == S_INT)
		sprintf(str, "%lld", val2);
	else
		sprintf(str, "0x%llx", val2);

	sym->curr.val = strdup(str);
}

static void sym_set_changed(struct symbol* sym)
{
	struct property* prop;

	sym->flags |= SYMBOL_CHANGED;

	for(prop = sym->prop; prop; prop = prop->next) {
		if(prop->menu)
			prop->menu->flags |= MENU_CHANGED;
	}
}

static void sym_set_all_changed(void)
{
	struct symbol* sym;
	int i;

	for_all_symbols(i, sym)
	sym_set_changed(sym);
}

static void sym_calc_visibility(struct symbol* sym)
{
	struct property* prop;
	struct symbol* choice_sym = NULL;
	tristate tri;

	/* any prompt visible? */
	tri = no;

	if(sym_is_choice_value(sym))
		choice_sym = prop_get_symbol(sym_get_choice_prop(sym));

	for_all_prompts(sym, prop) {
		prop->visible.tri = expr_calc_value(prop->visible.expr);

		/*
		 * Tristate choice_values with visibility 'mod' are
		 * not visible if the corresponding choice's value is
		 * 'yes'.
		 */
		if(choice_sym && sym->type == S_TRISTATE &&
		        prop->visible.tri == mod && choice_sym->curr.tri == yes)
			prop->visible.tri = no;

		tri = EXPR_OR(tri, prop->visible.tri);
	}

	if(tri == mod && (sym->type != S_TRISTATE || modules_val == no))
		tri = yes;

	if(sym->visible != tri) {
		sym->visible = tri;
		sym_set_changed(sym);
	}

	if(sym_is_choice_value(sym))
		return;

	/* defaulting to "yes" if no explicit "depends on" are given */
	tri = yes;

	if(sym->dir_dep.expr)
		tri = expr_calc_value(sym->dir_dep.expr);

	if(tri == mod)
		tri = yes;

	if(sym->dir_dep.tri != tri) {
		sym->dir_dep.tri = tri;
		sym_set_changed(sym);
	}

	tri = no;

	if(sym->rev_dep.expr)
		tri = expr_calc_value(sym->rev_dep.expr);

	if(tri == mod && sym_get_type(sym) == S_BOOLEAN)
		tri = yes;

	if(sym->rev_dep.tri != tri) {
		sym->rev_dep.tri = tri;
		sym_set_changed(sym);
	}

	tri = no;

	if(sym->implied.expr && sym->dir_dep.tri != no)
		tri = expr_calc_value(sym->implied.expr);

	if(tri == mod && sym_get_type(sym) == S_BOOLEAN)
		tri = yes;

	if(sym->implied.tri != tri) {
		sym->implied.tri = tri;
		sym_set_changed(sym);
	}
}

/*
 * Find the default symbol for a choice.
 * First try the default values for the choice symbol
 * Next locate the first visible choice value
 * Return NULL if none was found
 */
struct symbol* sym_choice_default(struct symbol* sym)
{
	struct symbol* def_sym;
	struct property* prop;
	struct expr* e;

	/* any of the defaults visible? */
	for_all_defaults(sym, prop) {
		prop->visible.tri = expr_calc_value(prop->visible.expr);

		if(prop->visible.tri == no)
			continue;

		def_sym = prop_get_symbol(prop);

		if(def_sym->visible != no)
			return def_sym;
	}

	/* just get the first visible value */
	prop = sym_get_choice_prop(sym);
	expr_list_for_each_sym(prop->expr, e, def_sym)

	if(def_sym->visible != no)
		return def_sym;

	/* failed to locate any defaults */
	return NULL;
}

static struct symbol* sym_calc_choice(struct symbol* sym)
{
	struct symbol* def_sym;
	struct property* prop;
	struct expr* e;
	int flags;

	/* first calculate all choice values' visibilities */
	flags = sym->flags;
	prop = sym_get_choice_prop(sym);
	expr_list_for_each_sym(prop->expr, e, def_sym) {
		sym_calc_visibility(def_sym);

		if(def_sym->visible != no)
			flags &= def_sym->flags;
	}

	sym->flags &= flags | ~SYMBOL_DEF_USER;

	/* is the user choice visible? */
	def_sym = sym->def[S_DEF_USER].val;

	if(def_sym && def_sym->visible != no)
		return def_sym;

	def_sym = sym_choice_default(sym);

	if(def_sym == NULL)
		/* no choice? reset tristate value */
		sym->curr.tri = no;

	return def_sym;
}

void sym_calc_value(struct symbol* sym)
{
	struct symbol_value newval, oldval;
	struct property* prop;
	struct expr* e;

	if(!sym)
		return;

	if(sym->flags & SYMBOL_VALID)
		return;

	if(sym_is_choice_value(sym) &&
	        sym->flags & SYMBOL_NEED_SET_CHOICE_VALUES) {
		sym->flags &= ~SYMBOL_NEED_SET_CHOICE_VALUES;
		prop = sym_get_choice_prop(sym);
		sym_calc_value(prop_get_symbol(prop));
	}

	sym->flags |= SYMBOL_VALID;

	oldval = sym->curr;

	switch(sym->type) {
		case S_INT:
		case S_HEX:
		case S_STRING:
			newval = symbol_empty.curr;
			break;

		case S_BOOLEAN:
		case S_TRISTATE:
			newval = symbol_no.curr;
			break;

		default:
			sym->curr.val = sym->name;
			sym->curr.tri = no;
			return;
	}

	if(!sym_is_choice_value(sym))
		sym->flags &= ~SYMBOL_WRITE;

	sym_calc_visibility(sym);

	/* set default if recursively called */
	sym->curr = newval;

	switch(sym_get_type(sym)) {
		case S_BOOLEAN:
		case S_TRISTATE:
			if(sym_is_choice_value(sym) && sym->visible == yes) {
				prop = sym_get_choice_prop(sym);
				newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
			} else {
				if(sym->visible != no) {
					/* if the symbol is visible use the user value
					 * if available, otherwise try the default value
					 */
					sym->flags |= SYMBOL_WRITE;

					if(sym_has_value(sym)) {
						newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
						                      sym->visible);
						goto calc_newval;
					}
				}

				if(sym->rev_dep.tri != no)
					sym->flags |= SYMBOL_WRITE;

				if(!sym_is_choice(sym)) {
					prop = sym_get_default_prop(sym);

					if(prop) {
						sym->flags |= SYMBOL_WRITE;
						newval.tri = EXPR_AND(expr_calc_value(prop->expr),
						                      prop->visible.tri);
					}

					if(sym->implied.tri != no) {
						sym->flags |= SYMBOL_WRITE;
						newval.tri = EXPR_OR(newval.tri, sym->implied.tri);
					}
				}

calc_newval:

				if(sym->dir_dep.tri == no && sym->rev_dep.tri != no) {
					struct expr* e;
					e = expr_simplify_unmet_dep(sym->rev_dep.expr,
					                            sym->dir_dep.expr);
					fprintf(stderr, "warning: (");
					expr_fprint(e, stderr);
					fprintf(stderr, ") selects %s which has unmet direct dependencies (",
					        sym->name);
					expr_fprint(sym->dir_dep.expr, stderr);
					fprintf(stderr, ")\n");
					expr_free(e);
				}

				newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
			}

			if(newval.tri == mod &&
			        (sym_get_type(sym) == S_BOOLEAN || sym->implied.tri == yes))
				newval.tri = yes;

			break;

		case S_STRING:
		case S_HEX:
		case S_INT:
			if(sym->visible != no) {
				sym->flags |= SYMBOL_WRITE;

				if(sym_has_value(sym)) {
					newval.val = sym->def[S_DEF_USER].val;
					break;
				}
			}

			prop = sym_get_default_prop(sym);

			if(prop) {
				struct symbol* ds = prop_get_symbol(prop);

				if(ds) {
					sym->flags |= SYMBOL_WRITE;
					sym_calc_value(ds);
					newval.val = ds->curr.val;
				}
			}

			break;

		default:
			;
	}

	sym->curr = newval;

	if(sym_is_choice(sym) && newval.tri == yes)
		sym->curr.val = sym_calc_choice(sym);

	sym_validate_range(sym);

	if(memcmp(&oldval, &sym->curr, sizeof(oldval))) {
		sym_set_changed(sym);

		if(modules_sym == sym) {
			sym_set_all_changed();
			modules_val = modules_sym->curr.tri;
		}
	}

	if(sym_is_choice(sym)) {
		struct symbol* choice_sym;

		prop = sym_get_choice_prop(sym);
		expr_list_for_each_sym(prop->expr, e, choice_sym) {
			if((sym->flags & SYMBOL_WRITE) &&
			        choice_sym->visible != no)
				choice_sym->flags |= SYMBOL_WRITE;

			if(sym->flags & SYMBOL_CHANGED)
				sym_set_changed(choice_sym);
		}
	}

	if(sym->flags & SYMBOL_AUTO)
		sym->flags &= ~SYMBOL_WRITE;

	if(sym->flags & SYMBOL_NEED_SET_CHOICE_VALUES)
		set_all_choice_values(sym);
}

void sym_clear_all_valid(void)
{
	struct symbol* sym;
	int i;

	for_all_symbols(i, sym)
	sym->flags &= ~SYMBOL_VALID;
	sym_add_change_count(1);
	sym_calc_value(modules_sym);
}

bool sym_tristate_within_range(struct symbol* sym, tristate val)
{
	int type = sym_get_type(sym);

	if(sym->visible == no)
		return false;

	if(type != S_BOOLEAN && type != S_TRISTATE)
		return false;

	if(type == S_BOOLEAN && val == mod)
		return false;

	if(sym->visible <= sym->rev_dep.tri)
		return false;

	if(sym->implied.tri == yes && val == mod)
		return false;

	if(sym_is_choice_value(sym) && sym->visible == yes)
		return val == yes;

	return val >= sym->rev_dep.tri && val <= sym->visible;
}

bool sym_set_tristate_value(struct symbol* sym, tristate val)
{
	tristate oldval = sym_get_tristate_value(sym);

	if(oldval != val && !sym_tristate_within_range(sym, val))
		return false;

	if(!(sym->flags & SYMBOL_DEF_USER)) {
		sym->flags |= SYMBOL_DEF_USER;
		sym_set_changed(sym);
	}

	/*
	 * setting a choice value also resets the new flag of the choice
	 * symbol and all other choice values.
	 */
	if(sym_is_choice_value(sym) && val == yes) {
		struct symbol* cs = prop_get_symbol(sym_get_choice_prop(sym));
		struct property* prop;
		struct expr* e;

		cs->def[S_DEF_USER].val = sym;
		cs->flags |= SYMBOL_DEF_USER;
		prop = sym_get_choice_prop(cs);

		for(e = prop->expr; e; e = e->left.expr) {
			if(e->right.sym->visible != no)
				e->right.sym->flags |= SYMBOL_DEF_USER;
		}
	}

	sym->def[S_DEF_USER].tri = val;

	if(oldval != val)
		sym_clear_all_valid();

	return true;
}

tristate sym_toggle_tristate_value(struct symbol* sym)
{
	tristate oldval, newval;

	oldval = newval = sym_get_tristate_value(sym);

	do {
		switch(newval) {
			case no:
				newval = mod;
				break;

			case mod:
				newval = yes;
				break;

			case yes:
				newval = no;
				break;
		}

		if(sym_set_tristate_value(sym, newval))
			break;
	} while(oldval != newval);

	return newval;
}

bool sym_string_valid(struct symbol* sym, const char* str)
{
	signed char ch;

	switch(sym->type) {
		case S_STRING:
			return true;

		case S_INT:
			ch = *str++;

			if(ch == '-')
				ch = *str++;

			if(!isdigit(ch))
				return false;

			if(ch == '0' && *str != 0)
				return false;

			while((ch = *str++)) {
				if(!isdigit(ch))
					return false;
			}

			return true;

		case S_HEX:
			if(str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
				str += 2;

			ch = *str++;

			do {
				if(!isxdigit(ch))
					return false;
			} while((ch = *str++));

			return true;

		case S_BOOLEAN:
		case S_TRISTATE:
			switch(str[0]) {
				case 'y':
				case 'Y':
				case 'm':
				case 'M':
				case 'n':
				case 'N':
					return true;
			}

			return false;

		default:
			return false;
	}
}

bool sym_string_within_range(struct symbol* sym, const char* str)
{
	struct property* prop;
	long long val;

	switch(sym->type) {
		case S_STRING:
			return sym_string_valid(sym, str);

		case S_INT:
			if(!sym_string_valid(sym, str))
				return false;

			prop = sym_get_range_prop(sym);

			if(!prop)
				return true;

			val = strtoll(str, NULL, 10);
			return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
			       val <= sym_get_range_val(prop->expr->right.sym, 10);

		case S_HEX:
			if(!sym_string_valid(sym, str))
				return false;

			prop = sym_get_range_prop(sym);

			if(!prop)
				return true;

			val = strtoll(str, NULL, 16);
			return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
			       val <= sym_get_range_val(prop->expr->right.sym, 16);

		case S_BOOLEAN:
		case S_TRISTATE:
			switch(str[0]) {
				case 'y':
				case 'Y':
					return sym_tristate_within_range(sym, yes);

				case 'm':
				case 'M':
					return sym_tristate_within_range(sym, mod);

				case 'n':
				case 'N':
					return sym_tristate_within_range(sym, no);
			}

			return false;

		default:
			return false;
	}
}

bool sym_set_string_value(struct symbol* sym, const char* newval)
{
	const char* oldval;
	char* val;
	int size;

	switch(sym->type) {
		case S_BOOLEAN:
		case S_TRISTATE:
			switch(newval[0]) {
				case 'y':
				case 'Y':
					return sym_set_tristate_value(sym, yes);

				case 'm':
				case 'M':
					return sym_set_tristate_value(sym, mod);

				case 'n':
				case 'N':
					return sym_set_tristate_value(sym, no);
			}

			return false;

		default:
			;
	}

	if(!sym_string_within_range(sym, newval))
		return false;

	if(!(sym->flags & SYMBOL_DEF_USER)) {
		sym->flags |= SYMBOL_DEF_USER;
		sym_set_changed(sym);
	}

	oldval = sym->def[S_DEF_USER].val;
	size = strlen(newval) + 1;

	if(sym->type == S_HEX && (newval[0] != '0' || (newval[1] != 'x' && newval[1] != 'X'))) {
		size += 2;
		sym->def[S_DEF_USER].val = val = xmalloc(size);
		*val++ = '0';
		*val++ = 'x';
	} else if(!oldval || strcmp(oldval, newval))
		sym->def[S_DEF_USER].val = val = xmalloc(size);
	else
		return true;

	strcpy(val, newval);
	free((void*)oldval);
	sym_clear_all_valid();

	return true;
}

/*
 * Find the default value associated to a symbol.
 * For tristate symbol handle the modules=n case
 * in which case "m" becomes "y".
 * If the symbol does not have any default then fallback
 * to the fixed default values.
 */
const char* sym_get_string_default(struct symbol* sym)
{
	struct property* prop;
	struct symbol* ds;
	const char* str;
	tristate val;

	sym_calc_visibility(sym);
	sym_calc_value(modules_sym);
	val = symbol_no.curr.tri;
	str = symbol_empty.curr.val;

	/* If symbol has a default value look it up */
	prop = sym_get_default_prop(sym);

	if(prop != NULL) {
		switch(sym->type) {
			case S_BOOLEAN:
			case S_TRISTATE:
				/* The visibility may limit the value from yes => mod */
				val = EXPR_AND(expr_calc_value(prop->expr), prop->visible.tri);
				break;

			default:
				/*
				 * The following fails to handle the situation
				 * where a default value is further limited by
				 * the valid range.
				 */
				ds = prop_get_symbol(prop);

				if(ds != NULL) {
					sym_calc_value(ds);
					str = (const char*)ds->curr.val;
				}
		}
	}

	/* Handle select statements */
	val = EXPR_OR(val, sym->rev_dep.tri);

	/* transpose mod to yes if modules are not enabled */
	if(val == mod)
		if(!sym_is_choice_value(sym) && modules_sym->curr.tri == no)
			val = yes;

	/* transpose mod to yes if type is bool */
	if(sym->type == S_BOOLEAN && val == mod)
		val = yes;

	/* adjust the default value if this symbol is implied by another */
	if(val < sym->implied.tri)
		val = sym->implied.tri;

	switch(sym->type) {
		case S_BOOLEAN:
		case S_TRISTATE:
			switch(val) {
				case no:
					return "n";

				case mod:
					return "m";

				case yes:
					return "y";
			}

		case S_INT:
		case S_HEX:
			return str;

		case S_STRING:
			return str;

		case S_OTHER:
		case S_UNKNOWN:
			break;
	}

	return "";
}

const char* sym_get_string_value(struct symbol* sym)
{
	tristate val;

	switch(sym->type) {
		case S_BOOLEAN:
		case S_TRISTATE:
			val = sym_get_tristate_value(sym);

			switch(val) {
				case no:
					return "n";

				case mod:
					sym_calc_value(modules_sym);
					return (modules_sym->curr.tri == no) ? "n" : "m";

				case yes:
					return "y";
			}

			break;

		default:
			;
	}

	return (const char*)sym->curr.val;
}

bool sym_is_changable(struct symbol* sym)
{
	return sym->visible > sym->rev_dep.tri;
}

static unsigned strhash(const char* s)
{
	/* fnv32 hash */
	unsigned hash = 2166136261U;

	for(; *s; s++)
		hash = (hash ^ *s) * 0x01000193;

	return hash;
}

struct symbol* sym_lookup(const char* name, int flags)
{
	struct symbol* symbol;
	char* new_name;
	int hash;

	if(name) {
		if(name[0] && !name[1]) {
			switch(name[0]) {
				case 'y':
					return &symbol_yes;

				case 'm':
					return &symbol_mod;

				case 'n':
					return &symbol_no;
			}
		}

		hash = strhash(name) % SYMBOL_HASHSIZE;

		for(symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
			if(symbol->name &&
			        !strcmp(symbol->name, name) &&
			        (flags ? symbol->flags & flags
			         : !(symbol->flags & (SYMBOL_CONST | SYMBOL_CHOICE))))
				return symbol;
		}

		new_name = strdup(name);
	} else {
		new_name = NULL;
		hash = 0;
	}

	symbol = xmalloc(sizeof(*symbol));
	memset(symbol, 0, sizeof(*symbol));
	symbol->name = new_name;
	symbol->type = S_UNKNOWN;
	symbol->flags |= flags;

	symbol->next = symbol_hash[hash];
	symbol_hash[hash] = symbol;

	return symbol;
}

struct symbol* sym_find(const char* name)
{
	struct symbol* symbol = NULL;
	int hash = 0;

	if(!name)
		return NULL;

	if(name[0] && !name[1]) {
		switch(name[0]) {
			case 'y':
				return &symbol_yes;

			case 'm':
				return &symbol_mod;

			case 'n':
				return &symbol_no;
		}
	}

	hash = strhash(name) % SYMBOL_HASHSIZE;

	for(symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
		if(symbol->name &&
		        !strcmp(symbol->name, name) &&
		        !(symbol->flags & SYMBOL_CONST))
			break;
	}

	return symbol;
}

/*
 * Expand symbol's names embedded in the string given in argument. Symbols'
 * name to be expanded shall be prefixed by a '$'. Unknown symbol expands to
 * the empty string.
 */
const char* sym_expand_string_value(const char* in)
{
	const char* src;
	char* res;
	size_t reslen;

	reslen = strlen(in) + 1;
	res = xmalloc(reslen);
	res[0] = '\0';

	while((src = strchr(in, '$'))) {
		char* p, name[SYMBOL_MAXLENGTH];
		const char* symval = "";
		struct symbol* sym;
		size_t newlen;

		strncat(res, in, src - in);
		src++;

		p = name;

		while(isalnum(*src) || *src == '_')
			*p++ = *src++;

		*p = '\0';

		sym = sym_find(name);

		if(sym != NULL) {
			sym_calc_value(sym);
			symval = sym_get_string_value(sym);
		}

		newlen = strlen(res) + strlen(symval) + strlen(src) + 1;

		if(newlen > reslen) {
			reslen = newlen;
			res = realloc(res, reslen);
		}

		strcat(res, symval);
		in = src;
	}

	strcat(res, in);

	return res;
}

const char* sym_escape_string_value(const char* in)
{
	const char* p;
	size_t reslen;
	char* res;
	size_t l;

	reslen = strlen(in) + strlen("\"\"") + 1;

	p = in;

	for(;;) {
		l = strcspn(p, "\"\\");
		p += l;

		if(p[0] == '\0')
			break;

		reslen++;
		p++;
	}

	res = xmalloc(reslen);
	res[0] = '\0';

	strcat(res, "\"");

	p = in;

	for(;;) {
		l = strcspn(p, "\"\\");
		strncat(res, p, l);
		p += l;

		if(p[0] == '\0')
			break;

		strcat(res, "\\");
		strncat(res, p++, 1);
	}

	strcat(res, "\"");
	return res;
}

struct sym_match {
	struct symbol*	sym;
	off_t		so, eo;
};

/* Compare matched symbols as thus:
 * - first, symbols that match exactly
 * - then, alphabetical sort
 */
static int sym_rel_comp(const void* sym1, const void* sym2)
{
	const struct sym_match* s1 = sym1;
	const struct sym_match* s2 = sym2;
	int exact1, exact2;

	/* Exact match:
	 * - if matched length on symbol s1 is the length of that symbol,
	 *   then this symbol should come first;
	 * - if matched length on symbol s2 is the length of that symbol,
	 *   then this symbol should come first.
	 * Note: since the search can be a regexp, both symbols may match
	 * exactly; if this is the case, we can't decide which comes first,
	 * and we fallback to sorting alphabetically.
	 */
	exact1 = (s1->eo - s1->so) == strlen(s1->sym->name);
	exact2 = (s2->eo - s2->so) == strlen(s2->sym->name);

	if(exact1 && !exact2)
		return -1;

	if(!exact1 && exact2)
		return 1;

	/* As a fallback, sort symbols alphabetically */
	return strcmp(s1->sym->name, s2->sym->name);
}

struct symbol** sym_re_search(const char* pattern)
{
	struct symbol* sym, **sym_arr = NULL;
	struct sym_match* sym_match_arr = NULL;
	int i, cnt, size;
	regex_t re;
	regmatch_t match[1];

	cnt = size = 0;

	/* Skip if empty */
	if(strlen(pattern) == 0)
		return NULL;

	if(regcomp(&re, pattern, REG_EXTENDED | REG_ICASE))
		return NULL;

	for_all_symbols(i, sym) {
		if(sym->flags & SYMBOL_CONST || !sym->name)
			continue;

		if(regexec(&re, sym->name, 1, match, 0))
			continue;

		if(cnt >= size) {
			void* tmp;
			size += 16;
			tmp = realloc(sym_match_arr, size * sizeof(struct sym_match));

			if(!tmp)
				goto sym_re_search_free;

			sym_match_arr = tmp;
		}

		sym_calc_value(sym);
		/* As regexec returned 0, we know we have a match, so
		 * we can use match[0].rm_[se]o without further checks
		 */
		sym_match_arr[cnt].so = match[0].rm_so;
		sym_match_arr[cnt].eo = match[0].rm_eo;
		sym_match_arr[cnt++].sym = sym;
	}

	if(sym_match_arr) {
		qsort(sym_match_arr, cnt, sizeof(struct sym_match), sym_rel_comp);
		sym_arr = malloc((cnt + 1) * sizeof(struct symbol));

		if(!sym_arr)
			goto sym_re_search_free;

		for(i = 0; i < cnt; i++)
			sym_arr[i] = sym_match_arr[i].sym;

		sym_arr[cnt] = NULL;
	}

sym_re_search_free:
	/* sym_match_arr can be NULL if no match, but free(NULL) is OK */
	free(sym_match_arr);
	regfree(&re);

	return sym_arr;
}

/*
 * When we check for recursive dependencies we use a stack to save
 * current state so we can print out relevant info to user.
 * The entries are located on the call stack so no need to free memory.
 * Note insert() remove() must always match to properly clear the stack.
 */
static struct dep_stack {
	struct dep_stack* prev, *next;
	struct symbol* sym;
	struct property* prop;
	struct expr* expr;
}* check_top;

static void dep_stack_insert(struct dep_stack* stack, struct symbol* sym)
{
	memset(stack, 0, sizeof(*stack));

	if(check_top)
		check_top->next = stack;

	stack->prev = check_top;
	stack->sym = sym;
	check_top = stack;
}

static void dep_stack_remove(void)
{
	check_top = check_top->prev;

	if(check_top)
		check_top->next = NULL;
}

/*
 * Called when we have detected a recursive dependency.
 * check_top point to the top of the stact so we use
 * the ->prev pointer to locate the bottom of the stack.
 */
static void sym_check_print_recursive(struct symbol* last_sym)
{
	struct dep_stack* stack;
	struct symbol* sym, *next_sym;
	struct menu* menu = NULL;
	struct property* prop;
	struct dep_stack cv_stack;

	if(sym_is_choice_value(last_sym)) {
		dep_stack_insert(&cv_stack, last_sym);
		last_sym = prop_get_symbol(sym_get_choice_prop(last_sym));
	}

	for(stack = check_top; stack != NULL; stack = stack->prev)
		if(stack->sym == last_sym)
			break;

	if(!stack) {
		fprintf(stderr, "unexpected recursive dependency error\n");
		return;
	}

	for(; stack; stack = stack->next) {
		sym = stack->sym;
		next_sym = stack->next ? stack->next->sym : last_sym;
		prop = stack->prop;

		if(prop == NULL)
			prop = stack->sym->prop;

		/* for choice values find the menu entry (used below) */
		if(sym_is_choice(sym) || sym_is_choice_value(sym)) {
			for(prop = sym->prop; prop; prop = prop->next) {
				menu = prop->menu;

				if(prop->menu)
					break;
			}
		}

		if(stack->sym == last_sym)
			fprintf(stderr, "%s:%d:error: recursive dependency detected!\n",
			        prop->file->name, prop->lineno);

		fprintf(stderr, "For a resolution refer to Documentation/kbuild/kconfig-language.txt\n");
		fprintf(stderr, "subsection \"Kconfig recursive dependency limitations\"\n");

		if(stack->expr) {
			fprintf(stderr, "%s:%d:\tsymbol %s %s value contains %s\n",
			        prop->file->name, prop->lineno,
			        sym->name ? sym->name : "<choice>",
			        prop_get_type_name(prop->type),
			        next_sym->name ? next_sym->name : "<choice>");
		} else if(stack->prop) {
			fprintf(stderr, "%s:%d:\tsymbol %s depends on %s\n",
			        prop->file->name, prop->lineno,
			        sym->name ? sym->name : "<choice>",
			        next_sym->name ? next_sym->name : "<choice>");
		} else if(sym_is_choice(sym)) {
			fprintf(stderr, "%s:%d:\tchoice %s contains symbol %s\n",
			        menu->file->name, menu->lineno,
			        sym->name ? sym->name : "<choice>",
			        next_sym->name ? next_sym->name : "<choice>");
		} else if(sym_is_choice_value(sym)) {
			fprintf(stderr, "%s:%d:\tsymbol %s is part of choice %s\n",
			        menu->file->name, menu->lineno,
			        sym->name ? sym->name : "<choice>",
			        next_sym->name ? next_sym->name : "<choice>");
		} else {
			fprintf(stderr, "%s:%d:\tsymbol %s is selected by %s\n",
			        prop->file->name, prop->lineno,
			        sym->name ? sym->name : "<choice>",
			        next_sym->name ? next_sym->name : "<choice>");
		}
	}

	if(check_top == &cv_stack)
		dep_stack_remove();
}

static struct symbol* sym_check_expr_deps(struct expr* e)
{
	struct symbol* sym;

	if(!e)
		return NULL;

	switch(e->type) {
		case E_OR:
		case E_AND:
			sym = sym_check_expr_deps(e->left.expr);

			if(sym)
				return sym;

			return sym_check_expr_deps(e->right.expr);

		case E_NOT:
			return sym_check_expr_deps(e->left.expr);

		case E_EQUAL:
		case E_GEQ:
		case E_GTH:
		case E_LEQ:
		case E_LTH:
		case E_UNEQUAL:
			sym = sym_check_deps(e->left.sym);

			if(sym)
				return sym;

			return sym_check_deps(e->right.sym);

		case E_SYMBOL:
			return sym_check_deps(e->left.sym);

		default:
			break;
	}

	printf("Oops! How to check %d?\n", e->type);
	return NULL;
}

/* return NULL when dependencies are OK */
static struct symbol* sym_check_sym_deps(struct symbol* sym)
{
	struct symbol* sym2;
	struct property* prop;
	struct dep_stack stack;

	dep_stack_insert(&stack, sym);

	sym2 = sym_check_expr_deps(sym->rev_dep.expr);

	if(sym2)
		goto out;

	for(prop = sym->prop; prop; prop = prop->next) {
		if(prop->type == P_CHOICE || prop->type == P_SELECT)
			continue;

		stack.prop = prop;
		sym2 = sym_check_expr_deps(prop->visible.expr);

		if(sym2)
			break;

		if(prop->type != P_DEFAULT || sym_is_choice(sym))
			continue;

		stack.expr = prop->expr;
		sym2 = sym_check_expr_deps(prop->expr);

		if(sym2)
			break;

		stack.expr = NULL;
	}

out:
	dep_stack_remove();

	return sym2;
}

static struct symbol* sym_check_choice_deps(struct symbol* choice)
{
	struct symbol* sym, *sym2;
	struct property* prop;
	struct expr* e;
	struct dep_stack stack;

	dep_stack_insert(&stack, choice);

	prop = sym_get_choice_prop(choice);
	expr_list_for_each_sym(prop->expr, e, sym)
	sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);

	choice->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
	sym2 = sym_check_sym_deps(choice);
	choice->flags &= ~SYMBOL_CHECK;

	if(sym2)
		goto out;

	expr_list_for_each_sym(prop->expr, e, sym) {
		sym2 = sym_check_sym_deps(sym);

		if(sym2)
			break;
	}
out:
	expr_list_for_each_sym(prop->expr, e, sym)
	sym->flags &= ~SYMBOL_CHECK;

	if(sym2 && sym_is_choice_value(sym2) &&
	        prop_get_symbol(sym_get_choice_prop(sym2)) == choice)
		sym2 = choice;

	dep_stack_remove();

	return sym2;
}

struct symbol* sym_check_deps(struct symbol* sym)
{
	struct symbol* sym2;
	struct property* prop;

	if(sym->flags & SYMBOL_CHECK) {
		sym_check_print_recursive(sym);
		return sym;
	}

	if(sym->flags & SYMBOL_CHECKED)
		return NULL;

	if(sym_is_choice_value(sym)) {
		struct dep_stack stack;

		/* for choice groups start the check with main choice symbol */
		dep_stack_insert(&stack, sym);
		prop = sym_get_choice_prop(sym);
		sym2 = sym_check_deps(prop_get_symbol(prop));
		dep_stack_remove();
	} else if(sym_is_choice(sym)) {
		sym2 = sym_check_choice_deps(sym);
	} else {
		sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
		sym2 = sym_check_sym_deps(sym);
		sym->flags &= ~SYMBOL_CHECK;
	}

	if(sym2 && sym2 == sym)
		sym2 = NULL;

	return sym2;
}

struct property* prop_alloc(enum prop_type type, struct symbol* sym)
{
	struct property* prop;
	struct property** propp;

	prop = xmalloc(sizeof(*prop));
	memset(prop, 0, sizeof(*prop));
	prop->type = type;
	prop->sym = sym;
	prop->file = current_file;
	prop->lineno = zconf_lineno();

	/* append property to the prop list of symbol */
	if(sym) {
		for(propp = &sym->prop; *propp; propp = &(*propp)->next)
			;

		*propp = prop;
	}

	return prop;
}

struct symbol* prop_get_symbol(struct property* prop)
{
	if(prop->expr && (prop->expr->type == E_SYMBOL ||
	                  prop->expr->type == E_LIST))
		return prop->expr->left.sym;

	return NULL;
}

const char* prop_get_type_name(enum prop_type type)
{
	switch(type) {
		case P_PROMPT:
			return "prompt";

		case P_ENV:
			return "env";

		case P_COMMENT:
			return "comment";

		case P_MENU:
			return "menu";

		case P_DEFAULT:
			return "default";

		case P_CHOICE:
			return "choice";

		case P_SELECT:
			return "select";

		case P_IMPLY:
			return "imply";

		case P_RANGE:
			return "range";

		case P_SYMBOL:
			return "symbol";

		case P_UNKNOWN:
			break;
	}

	return "unknown";
}

static void prop_add_env(const char* env)
{
	struct symbol* sym, *sym2;
	struct property* prop;
	char* p;

	sym = current_entry->sym;
	sym->flags |= SYMBOL_AUTO;
	for_all_properties(sym, prop, P_ENV) {
		sym2 = prop_get_symbol(prop);

		if(strcmp(sym2->name, env))
			menu_warn(current_entry, "redefining environment symbol from %s",
			          sym2->name);

		return;
	}

	prop = prop_alloc(P_ENV, sym);
	prop->expr = expr_alloc_symbol(sym_lookup(env, SYMBOL_CONST));

	sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
	sym_env_list->right.sym = sym;

	p = getenv(env);

	if(p)
		sym_add_default(sym, p);
	else
		menu_warn(current_entry, "environment variable %s undefined", env);
}
